Blood processing equipment such as centrifuges which are conventionally used to separate the blood into its various constituents such as red blood cells, platelets and plasma require sophisticated and complex process control equipment. Such process controllers often take the form of an electronic controller provided with an input/output CRT terminal. It is desirable that such equipment be extendable to a lifted position during use, and it is capable of being lowered to a storage position during transport or storage of the equipment.
A simple and economical device is needed to assist in lifting of the process control mechanism so that it can be handled by hospital personnel who may not have sufficient or physical or lifting strength to lift heavy objects, particularly to an elevated position which may be somewhat above the head of the operator. When conventional springs are used to provide such lifting assistance, the problem exists of the spring being under increasingly greater tension as the mechanism is lowered. Thus, excessive upward force is applied on the mechanism when it is first released. This raises the possibility of injury to personnel or damage to the equipment being supported.
A need has, thus, existed for a lift mechanism for supporting poles which is both economical and effective in lifting of the equipment.
It is an object of the present invention to provide a lift assisting mechanism for supporting poles used on blood processing equipment. In accordance with an important aspect of the invention, such a lift mechanism is provided which is economical but which provides a uniform lifting force to the mechanism as it is raised and lowered.
In accordance with a further aspect of the invention, a pole lift mechanism is provided which utilizes at least one constant force spring and preferably two of such springs to provide an even and uniform lift assisting force on the mechanism. In accordance with a yet further aspect of the invention, the supporting pole is provided with such constant spring lift mechanisms which work in conjunction with a series of bearings which facilitate raising and lowering of the supporting pole.
Briefly, a support assembly for process control equipment according to the invention includes a cabinet containing processing equipment. A vertical support pole is supported on said cabinet through a collar for extension and retraction. Process control equipment such as electronic control equipment and a video monitor is mounted on the upper end of the pole. At least one, and preferably two constant force springs biased into a fully coiled position are attached at one end to the lower end of the pole. The opposite end of the springs are mounted for free rotation on a spool which is secured to the cabinet, whereby raising and lowering of the process control equipment is facilitated.
Further objects and advantages of the invention will become apparent from the following detailed description, the claims and the accompanying drawings.